Was browsing through Sharpe's book the other night, and got to looking at the old powders again.
I've seen Hi Vel #2 listed next to Reloader 7 on one chart, but has anyone ever seen the relative position of Hi Vel #3?
Sharpe seemed to indicate that Hi Vel #3 was faster than Hi Vel #2.

HiVel #3 was a double-base powder with a lot of nitroglycerin.  It became chemically unstable at very low (sub-zero) temperatures.  The nitroglycerin separated and detonated.  Not good for either shooter or rifle.

That is what killed off the .401 WSL cartridge and led to abandoning the Model 1910 Winchester autoloader in the 1930s.

I read somewhere that the burn rate was close to 4227 or to the old 2400.

Here's a few notes from Sharpe's book (1937)...

For HiVel #2:
     "HiVel #2 is a double-based powder with about 15% of nitroglycerine."
      "It has been asserted by some authorities that HiVel is highly erosive, but it is believed that this statement is in error. Despite the fact that it has a greater potential, this powder requires a much lower weight of charge to develop equal velocities, and this, together with lower pressure, more than offsets the combustion temperature."

For Hercules #2400:
     "It is a very fine-grained dense type, similar in composition to HiVel."

For HiVel #3:
     "... Although first produced in 1926, it was not released to the cannister trade until early in the summer of 1935. It is slightly smaller in granulation than HiVel #2, runs reasonably well through the average powder measure and is superbly accurate and flexible. In the .300 Savage a charge as low as 10 grains can be used behind a 154-grain plain lead-based bullet developing a velocity of 1180 f.s. and a pressure too low to register. A charge of 16 grains with the same bullet gives a velocity of 1460 f.s. with a pressure of only 8400. By the same token, it operates excellently at pressures as high as 50,000 pounds or more, and in the .300 Savage with the 180-grain 30/06 bullet, 31.5 grains gives a muzzle velocity of 2420 with a pressure of 49,000 pounds. ..."

waterman,
Do you remember where you got the info on the nitroglycerin separation and detonation at sub-zero temps?

Frank,
It's long gone from dealers shelves, but it turns out that it ain't all gone.   

I came into shooting just about five years before Hivel #2 was discontinued. It was a great Powder worked well in everything from 25-35 up to 30-06 with heavy charges. One that stands out in my mind which I did shoot with success was 39 gr Hivel#2 behind a 180 Gr Spitzer Flat Base bullet from Sierra. In a 30-06 M70 Target it Shot very well out to 300 Yds. I was disappointed when it went off the Market and for many years after I bought all I could find where ever it was. But it slowly disappeared. Regards FITZ.

waterman,

Read through the section on powder storage & handling in Sharpe's book, but no mention of the .401 WSL or 44 WCF HiVel incident there.

Don't know when the 44 WCF HiVel production ceased, but the 32 WCF HiVel is said to have continued to the late 60's and maybe early 70's, depending on manufacturer.

waterman,

Thank you for locating that citation, and the approximate burn rate.
Interesting information!

There is also the attribute of energy content that relates to burn rate. While the burn rate may be the same or similar, the energy content can be higher and escalate pressures. The old powder charges are for a by-gone era and I will not take a chance on sacrificing a rifle for savings or convenience. 

The powder companies cannot exactly reproduce the powder from lot to lot. The powder sold to handloaders is tested and tested to assure it is within a narrow band for burn rate, energy content and stabilization. Any powder outside of these limits is sold to the ammo makers with a table exactly defining the burn rate, energy content stability for the ammo maker's reloading usage.